In some wells, it is desirable to individually and selectively create multiple fractures having adequate conductivity, usually a significant distance apart along a wellbore, so that as much of the hydrocarbons in an oil and gas reservoir as possible can be drained/produced into the wellbore.
The best known way to achieve desired hydraulic fracturing isolation/results is to cement a solid liner in the lateral section of the wellbore, perform a conventional explosive perforating step, and then perform fracturing stages along the wellbore using some technique for mechanically isolating the individual fractures.
Traditional methods to create fractures at predetermined points along a highly deviated or horizontal wellbore vary depending on the nature of the completion within the lateral (or highly deviated) section of the wellbore.
When fracturing a reservoir from a wellbore, especially those that are highly deviated or horizontal, it is difficult to control the creation of multi-zone fractures along the wellbore without cementing a liner to the wellbore and mechanically isolating the zone being fractured from previously fractured zones or zones not yet fractured. However, only a small percentage of the horizontal completions during the past 15 or more years used a cemented liner type completion; most used some type of non-cemented liner or a bare open hole section. Furthermore, many wells with cemented liners in the lateral were also completed with a significant length of open hole section beyond the cemented liner section.
More recently, Halliburton Energy Services, Inc. has introduced and proven the technology for using hydrajet perforating, jetting while fracturing, and co-injection down the annulus. In one method, this process is generally referred to by Halliburton as the SURGIFRAC® process or stimulation method and is described in U.S. Pat. No. 5,765,642, which is incorporated herein by reference. The SURGIFRAC® process has been applied mostly to horizontal or highly deviated wellbores, where casing the hole is difficult and expensive. By using this hydrajetting technique, it is possible to generate one or more independent, single plane hydraulic fractures; and therefore, highly deviated or horizontal wells can be often completed without having to case the wellbore. Furthermore, even when highly deviated or horizontal wells are cased, hydrajetting the perforations and fractures in such wells generally result in a more effective fracturing method than using traditional explosive charge perforation and fracturing techniques. Thus, prior to the SURGIFRAC® technique, methods available were usually too costly to be an economic alternative, or generally ineffective in achieving stimulation results, or both.
In view of the success of the SURGIFRAC® process, improvements and extensions of the basic SURGIFRAC® process are desirable.
Patent publications generally relating to jetting in downhole applications include the following.
U.S. Pat. No. 5,226,445 issued Jul. 13, 1993, having for named inventor Jim B. Surjaatmadja, filed on May 5, 1992 discloses in the Abstract thereof a valve that includes a seat surrounding an orifice having a concave seating surface and a plug having an annular sealing surface for sealingly contacting the seat. The sealing surface is convex and creates a convex discontinuity in an axially-extending, cross-sectional profile of the plug. The sealing surface retains approximately the same amount of contact area with the seating surface when the plug is misaligned or tilted with respect to the seat as when aligned. The entirety of U.S. Pat. No. 5,226,445 is incorporated herein by reference.
U.S. Pat. No. 5,249,628 issued Oct. 5, 1993, having for named inventor Jim B. Surjaatmadja, and filed on Sep. 29, 1992 discloses in the Abstract thereof casing slip joints provided on opposite sides of a fracture initiation location to accommodate casing and formation movement during fracturing of a well. In another aspect of the invention, the fracture initiation location is provided by forming openings through the well casing and then forming fan-shaped slots in the formation surrounding the casing. Those slots are formed by a hydraulic jet which is directed through the opening and then pivoted generally about the point of the opening. These fan-shaped slots circumscribe an angle about the axis of the casing substantially greater than the angle circumscribed by the opening itself through which the slot was formed. These techniques are particularly applicable to fracturing of horizontal wells. The entirety of U.S. Pat. No. 5,249,628 is incorporated herein by reference.
U.S. Pat. No. 5,361,856 issued Nov. 8, 1994, having for named inventors Jim B. Surjaatmadja, Steven L. Holden, and David D. Szarka, and filed on Sep. 9, 1993, discloses in the Abstract thereof a well jetting apparatus for use in fracturing of a well. Fracture initiation is provided by forming openings through the well casing and then forming fan-shaped slots in the formation surrounding the casing. Those slots are formed by the jetting apparatus which has at least one hydraulic jet directed through the opening. The apparatus may be pivoted generally about the point of the opening to form the slots, but preferably a plurality of slots are formed substantially simultaneously. These fan-shaped slots circumscribe an angle about the axis of the casing substantially greater than the angle circumscribed by the opening itself through which the slot was formed. These techniques are particularly applicable to fracturing of horizontal wells, but the apparatus may be used in any well configuration. The entirety of U.S. Pat. No. 5,361,856 is incorporated herein by reference.
U.S. Pat. No. 5,396,957 issued Mar. 14, 1995, having for named inventors Jim B. Surjaatmadja, Timothy W. Helton, and Danny G. Porter, and filed on Mar. 4, 1994 discloses in the Abstract thereof expandable casing portions, such as casing slip joints or expansion joints, on opposite sides of a fracture initiation location to accommodate casing and formation movement during fracturing of a well. The fracture initiation location provided by forming openings through the well casing and then forming fan-shaped slots in the formation surrounding the casing. These fan-shaped slots circumscribe an angle about the axis of the casing substantially greater than the angle circumscribed by the opening itself through which the slot was formed. These techniques are particularly applicable to fracturing of horizontal wells, but are also useful on vertical wells. The expansion joints formed as tubular members having alternating inner and outer annular grooves. In another embodiment, the expansion joints formed by tubular members defining alternating inner and outer spiral grooves therein. The entirety of U.S. Pat. No. 5,396,957 is incorporated herein by reference.
U.S. Pat. No. 5,499,678 issued Mar. 19, 1996, having for named inventors Jim B. Surjaatmadja, Timothy W. Helton, and Hazim H. Abass, and filed on Aug. 2, 1994 discloses in the Abstract thereof a coplanar jetting head for well perforating. The apparatus comprises a housing defining a plurality of jetting openings therein. The jetting openings are substantially coplanar and are angularly disposed with respect to a longitudinal axis of the housing. Each of the jetting openings has a jetting nozzle disposed therein. In the preferred embodiment, the angle of the plane of the jetting openings is such that the plane may be positioned substantially perpendicular to an axis of least principal stress in a well formation adjacent to the well bore when the housing is disposed in the well bore. A method of fracturing a well is also disclosed and comprises the steps of positioning a jetting head in a well bore and directing a plurality of fluid jets from the jetting head at an angle with respect to the longitudinal axis of the well bore. The entirety of U.S. Pat. No. 5,499,678 is incorporated herein by reference.
U.S. Pat. No. 5,765,642 issued Jun. 16, 1998, having for named inventor Jim B. Surjaatmadja, and filed on Dec. 23, 1996 discloses in the Abstract thereof methods of fracturing a subterranean formation, which basically comprise positioning a hydrajetting tool having at least one fluid jet forming nozzle in the well bore adjacent the formation to be fractured and jetting fluid through the nozzle against the formation at a pressure sufficient to form a fracture in the formation. The entirety of U.S. Pat. No. 5,765,642 is incorporated herein by reference.
U.S. Pat. No. 6,474,419 issued Nov. 5, 2002, having for named inventors Gary Maier, Marty L. Stromquist, and Eric Schmelzl and filed on Oct. 4, 1999 discloses in the Abstract thereof a packer with an equalizing valve for automatically equalizing the pressure above and below the packer element. The packer comprises a housing having an equalizing valve disposed therein. A packer element is disposed about the housing for sealingly engaging the wellbore. An equalizing valve is disposed in the housing and seals the housing to prevent flow therethrough when the packer element is actuated to engage the wellbore. The valve is movable in the closed position wherein communication through the housing is prevented to an open position so that the portion of the wellbore above the packer element may be communicated with a portion of the wellbore below the packer element while the element is in the set position so that pressure above and below the element may be equalized. Once the pressure is equalized, the packer can be unset and retrieved from the wellbore. The entirety of U.S. Pat. No. 6,474,419 is incorporated herein by reference.
U.S. Pat. No. 6,662,874 issued Dec. 16, 2003, having for named inventors Jim B. Surjaatmadja, Alick Cheng, and Keith A. Rispler, and filed on Sep. 28, 2001 discloses in the Abstract thereof a method of fracturing a downhole formation according to which a plurality of jet nozzles are located in a spaced relation to the wall of the formation to form an annulus between the nozzles and the formation. A non-acid containing stimulation fluid is pumped at a predetermined pressure through the nozzles, into the annulus, and against the wall of the formation, and a gas is introduced into the annulus so that the stimulation fluid mixes with the gas to generate foam before the mixture is jetted towards the formation to form fractures in the formation. The entirety of U.S. Pat. No. 6,662,874 is incorporated herein by reference.
U.S. Pat. No. 6,719,054 issued Apr. 13, 2004, having for named inventors Alick Cheng, Jim B. Surjaatmadja, Matthew J. Rees, Abraham Khallad, and Kieth A. Rispler, and filed on Sep. 28, 2001 discloses in the Abstract thereof a method of stimulating a downhole formation according to which a plurality of jet nozzles are located in a spaced relation to the wall of the formation to form an annulus between the nozzles and the formation. An acid-containing, stimulation fluid is pumped at a predetermined pressure through the nozzles, into the annulus and against the wall of the formation. A gas is pumped into the annulus so that the stimulation fluid mixes with the gas to generate foam before the mixture is jetted towards the formation to impact the wall of the formation. The entirety of U.S. Pat. No. 6,719,054 is incorporated herein by reference.
U.S. Pat. No. 6,725,933 issued Apr. 27, 2004, having for named inventors Richard L. Middaugh and Jim B. Surjaatmadja, and filed on Sep. 28, 2001 discloses in the Abstract thereof a method and apparatus for treating a subterranean well formation to stimulate the production of hydrocarbons utilizing foam diversion in the well formation. The entirety of U.S. Pat. No. 6,725,933 is incorporated herein by reference.
U.S. Pat. No. 6,776,236 issued Aug. 17, 2004, having for named inventor Phillip D. Nguyen, and filed on Oct. 16, 2002, discloses in the Abstract thereof methods of completing unconsolidated hydrocarbon producing zones penetrated by cased and cemented well bores. The methods include the steps of forming spaced openings through the casing and cement and injecting a first hardenable resin composition through the openings into the unconsolidated producing zone adjacent to the well bore. Without waiting for the first hardenable resin composition to harden, a fracturing fluid containing proppant particles coated with a second hardenable resin composition is injected through the openings into the unconsolidated producing zone at a rate and pressure sufficient to fracture the producing zone. The proppant particles coated with the second hardenable resin composition are deposited in the fractures and the first and second hardenable resin compositions are allowed to harden by heat. The entirety of U.S. Pat. No. 6,776,236 is incorporated herein by reference.
U.S. Pat. No. 6,779,607 issued Aug. 24, 2004, having for named inventors Richard L. Middaugh and Jim B. Surjaatmadja, and filed on Jun. 26, 2003 discloses in the Abstract thereof a method and apparatus or treating a subterranean well formation to stimulate the production of hydrocarbons utilizing foam diversion in the well formation. The entirety of U.S. Pat. No. 6,779,607 is incorporated herein by reference.
U.S. Patent Publication No. 20050211439 published on Sep. 28, 2005, having for named inventors Ronald M. Willett, Jim B. Surjaatmadja, and Billy W. McDaniel, and filed on Mar. 24, 2004 discloses in the Abstract thereof a method of isolating hydrajet stimulated zones from subsequent well operations. The method includes the step of drilling a wellbore into the subterranean formation of interest. Next, the wellbore may or may not be cased depending upon a number of factors including the nature and structure of the subterranean formation. Next, the casing, if one is installed, and wellbore are perforated using a high pressure fluid being ejected from a hydrajetting tool. A first zone of the subterranean formation is then fractured and stimulated. Next, the first zone is temporarily plugged or partially sealed by installing an isolation fluid into the wellbore adjacent to the one or more fractures and/or in the openings thereof, so that subsequent zones can be fractured and additional well operations can be performed. The entirety of U.S. Patent Publication No. 20050211439 is incorporated herein by reference.
U.S. Patent Publication No. 20060118301 published on Jun. 8, 2006, having for named inventors Loyd E. East, Jr., Travis W. Cavender, David J. Attaway, and filed on Dec. 3, 2004 discloses in the Abstract thereof a method of stimulating a production interval adjacent a well bore having a casing disposed therein, that comprises introducing a carrier fluid comprising first particulates into the well bore, packing the first particulates into a plurality of perforations in the casing, perforating at least one remedial perforation in the casing adjacent to the production interval, and stimulating the production interval through the at least one remedial perforation. Also provided are methods of stimulating multiple production intervals adjacent a well bore. The entirety of U.S. Patent Publication No. is incorporated herein by reference.